胰岛素促进心肌成纤维细胞增殖和心肌细胞肥大的作用

目的:研究胰岛素对心脏细胞增殖和心肌细胞肥大的影响,探讨其在心肌肥厚中的作用。方法:①乳鼠心肌细胞和心肌成纤维细胞的培养及光镜、电镜和免疫细胞化学染色的鉴定。②测定细胞的数量、代谢活性(WST-1)与DNA合成(BrdUELISA法)及细胞周期百分比(流式细胞仪)以反映细胞增殖。③用细胞蛋白含量(考马斯亮蓝法)评估细胞肥大。结果:①培养的细胞分别为心肌细胞和心肌成纤维细胞。②胰岛素处理后,心肌成纤维细胞数量、WST-1与BrdU的吸光值及S+G₂+M期细胞百分比明显升高(P＜0.01或P＜0.05),而心肌细胞的上述参数无明显变化(P＞0.05)。③胰岛素作用下,心肌细胞蛋白含量明显增加,且在10^-10mol/L-10^-7mol/L范围内呈量效关系(P＜0.01或P＜0.05)。结论:在体外胰岛素有促进心肌成纤维细胞增殖和增加心肌细胞蛋白含量(诱导心肌细胞肥大)的作用,可能在体内心肌肥厚的发生发展过程中起重要作用。

Effects of insulin on cardiac fibroblast proliferation and cardiac myocyte hypertrophy

AIM: To study the effect of insulin on proliferation and hypertrophy of cardiac myocytes and its role in the induction of cardiac hypertrophy. METHODS: 1. The neonatal rat cardiac myocytes and cardiac fibroblasts were cultured respectively and identified with light microscopy, electron microscopy and immunocytochemistry. 2. Cell proliferation was measured with cell number, metabolic activity and DNA synthesis (with WST-1, BrdU enzyme-linked immunosorbent assay ) and the percentage of S+G 2+M in cell cycle (by flow cytometry ). 3.Cell hypertrophy was evaluated by cell protein content (Coomassie Briliant Blue's method). RESULTS: 1. The cultured cells showed the characteristic of cardiac myocytes and cardiac fibroblasts, respectively. 2. After being treated with insulin, the cell number, absorbance of BrdU incorporation and WST-1 cleavage products and the percentage of S+G 2+M of cardiac fibroblasts increased significantly ( P< 0.01 or P< 0.05), while the above parameters of cardiac myocytes remained unchanged ( P> 0.05). 3. Protein content of cardiac myocytes increased significantly in a dose-dependent manner ( P< 0.01 or P< 0.05) in insulin treated groups (10 -10 mol/L-10 -7 mol/L). CONCLUSION: Insulin promoted cardiac fibroblast proliferation and increased myocytes protein content(induced myocyte hypertrophy) in vitro and may play an important role in pathogenesis of cardiac hypertrophy in vivo.